Drum washing machine

ABSTRACT

A drum washing machine which reduces the number of balance weights installed on the rear surface of a tub, and prevents the tub from being cracked due to eccentric rotation. The drum washing machine includes a bearing housing installed on the tub for supporting a rotary shaft; and a bearing housing bracket fixing the bearing housing to the tub, and serving as a balance weight for reducing vibration generated due to the eccentric rotation of a rotary drum. The drum washing machine further includes a balance weight detachably attached to the tub separately from the bearing housing bracket. The bearing housing bracket may be made of cast iron. The weight of the bearing housing bracket may be at least three times the weight of the balance weight. The thickness of the bearing housing bracket is gradually reduced from an opening to an edge portion.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 2005-11026, filed Feb. 5, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a drum washing machine and, more particularly, to a bearing housing bracket installed on the rear surface of a tub of a drum washing machine.

2. Description of the Related Art

Generally, a drum washing machine washes laundry by rotating a rotary drum using the rotary force of a driving motor, and dehydrates the laundry by rotating the rotary drum at a high speed. The dehydration of the laundry in the drum washing machine is achieved by centrifugally separating moisture from the laundry by means of centrifugal force applied to the laundry in the drum washing machine by rotating the rotary drum at the high speed. During the dehydration, which is achieved by the high-speed rotation of the rotary drum, the partial disposition of the laundry in the rotary drum generates severe vibration and noise. In order to prevent the generation of noise, balance weight devices are installed in the drum washing machine. Generally, the balance weight devices are respectively fixed to the front and rear surfaces of a tub by bolts.

Korean Utility Model Publication No. 20-0145371 discloses a drum washing machine, in which balance weight devices are respectively installed on the front and upper surfaces of a tub.

Since a plurality of the balance weight devices are installed on the front and upper surfaces of the tub, the number of components of the drum washing machine is increased, and the number of steps of an assembly process of the drum washing machine is thus increased, thereby deteriorating efficiency in assembling the drum washing machine.

Although the balance weight devices are installed in the drum washing machine, when a rotary drum is rotated at a high speed, the rotary drum is eccentrically rotated by the partial disposition of laundry, thereby causing distortion of a bearing housing supporting a rotary shaft. When the distortion is transmitted to the tub, the tub is cracked.

Further, since a plurality of the balance weight devices are installed on the tub, it is difficult to maintain the balance of weights between left and right sides of the tub.

SUMMARY OF THE INVENTION

Therefore, one aspect of the invention is to provide a drum washing machine which reduces the number of balance weight devices installed on a tub, thereby reducing the number of steps of an assembly process and improving efficiency in assembling the drum washing machine.

Another aspect of the invention is to provide a drum washing machine which decreases the degree of eccentric rotation of a rotary drum.

Yet another aspect of the invention is to provide a drum washing machine which easily maintains the balance of weights between left and right sides of a tub.

An apparatus consistent with the present invention provides a drum washing machine comprising a tub; a rotary drum installed in the tub; a rotary shaft extended from the rotary drum to the outside of the tub by passing through the tub; a bearing housing installed on the tub for supporting the rotary shaft; and a bearing housing bracket fixing the bearing housing to the tub, and serving as a balance weight for reducing vibration generated due to the eccentric rotation of the rotary drum.

The drum washing machine may further comprise a separate balance weight detachably attached to the tub separately from the bearing housing bracket.

Further, the bearing housing bracket and the separate balance weight may be installed on the rear surface of the tub.

Moreover, the weight of the bearing housing bracket may be at least three times the weight of the separate balance weight.

The bearing housing bracket may be made of cast iron.

The bearing housing bracket includes an opening formed through the central portion thereof for passing the bearing housing; and an edge portion, through which a plurality of fixing holes are formed so that the bearing housing bracket is fixed to the rear surface of the tub by fasteners passing through the fixing holes.

The thickness of the bearing housing bracket may be gradually reduced from the opening to the edge portion.

Further, the tub may be fixed to a housing so that the tub is downwardly inclined from the front surface of the tub to the rear surface of the tub.

Moreover, the bearing housing and the bearing housing bracket may be unitarily formed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will become apparent and more readily appreciated from the following description of the exemplary embodiments, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a longitudinal sectional view of a drum washing machine consistent with the present invention;

FIG. 2 is an exploded perspective view illustrating the connection structure between a bearing housing and a bearing housing bracket of the drum washing machine of the present invention;

FIG. 3 is a perspective view of the bearing housing and the bearing housing bracket of the drum washing machine of the present invention in a state in which the bearing housing and the bearing housing bracket are connected;

FIG. 4 is a sectional view illustrating the connection structure between a bearing housing and a bearing housing bracket in accordance with a first embodiment of the present invention; and

FIG. 5 is a sectional view illustrating the connection structure between a bearing housing and a bearing housing bracket in accordance with a second embodiment of the present invention.

DETAILED DESCRIPTION OF THE ILLUSTRATIVE, NON-LIMITING EMBODIMENTS OF THE INVENTION

Reference will now be made in detail to the illustrative, non-limiting embodiments of the present invention, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The exemplary embodiments are described below to explain the present invention by referring to the accompanying drawings.

As shown in FIG. 1, a drum washing machine of the present invention comprises a housing 10 forming the external appearance of the drum washing machine, a tub 11 installed in the housing 10 for containing washing water, and a rotary drum 12 rotatably installed in the tub 11 for washing laundry placed therein.

The tub 11, which is installed in the housing 10 for containing the rotary drum 12 having a cylindrical structure, is fixed to the housing 10 through suspension springs 14 and suspension arms 15. Both side surfaces of the tub 11 are fixed to the upper part of the housing 10 by two suspension springs 14, and the lower part of the tub 11 is elastically supported by four suspension arms 15 and fixed to the lower part of the housing 10. The length of the front suspension arms 15 a for supporting the lower part of the front portion of the tub 11 is longer than the length of the rear suspension arms 15 b for supporting the lower part of the rear portion of the tub 11, so that the tub 11 is fixed to the housing 10 under the condition that the tub 11 is downwardly inclined from the front surface 11 b of the tub 11 to the rear surface 11 a of the tub 11.

The above inclined structure of the tub 11 assists a user to take laundry out of the tub 11, and concentrates the weight onto a rotary shaft 30 rotating and supporting the rotary drum 12, thereby reducing the degree of eccentric rotation of the rotary drum 12 when the rotary drum 12 is rotated.

An opening 17, through which laundry is inserted into the rotary drum 12, is formed through the front surface of the housing 10, and a door 19 for opening and closing the opening 17 is installed at the opening 17. A water supply valve 21 for controlling the supply of water and a detergent supply device 22 for supplying a detergent to the inside of the tub 11 are installed above the tub 11, and a drainage valve 23 opened and closed for discharging water in the tub 11 and a drainage pump 24 for forcibly discharging the water in the tub 11 to the outside are installed below the tub 11.

A plurality of through-holes 25 for circulating washing water therethrough are formed through the cylindrical surface of the rotary drum 12, and a plurality of lifters 26 for lifting the laundry in the rotary drum 12 and then dropping the laundry are installed on the inner surface of the rotary drum 12.

The rotary shaft 30 fixed to the central portion of the rear surface of the rotary drum 12 is supported by the rear surface of the tub 11, thereby allowing the rotary drum 12 to be rotated in the tub 11. The rear end of the rotary shaft 30 is fixed to a pulley 31, and the pulley 31 is connected to a driving motor 33 installed in the lower portion of the housing 10 by a belt 32. Thereby, the driving force of the driving motor 33 is transmitted to the rotary shaft 30.

A bearing housing 50, which contains a bearing member 34 located at the inner cylindrical surface thereof for simultaneously supporting and passing the rotary shaft 30 under the condition that the rotary shaft 30 is rotatable, is installed on the rear surface of the tub 11. In order to firmly attach the bearing housing 50 to the tub 11, a bearing housing bracket 60 intervening therebetween is utilized.

Hereinafter, with reference to FIGS. 2 to 5, the connection structure between the bearing housing 50 and the tub 11 through the bearing housing bracket 60, and the characteristics of the bearing housing bracket 60 will be described in detail.

As shown in FIG. 2, the bearing housing 50, which contains the bearing member 34 located at the inner cylindrical surface thereof for simultaneously supporting and passing the rotary shaft 30 under the condition that the rotary shaft 30 is rotatable, is installed on the central portion of the rear surface 11 a of the tub 11.

The bearing housing 50 includes a body portion 51 protruded from the rear surface 11 a of the tub 11 for containing the bearing member 34, and a fringe portion 52 which abuts the rear surface 11 a of the tub 11.

The bearing housing bracket 60 has a disk shape such that an opening 61 for passing the body portion 51 of the bearing housing 50 is formed through the central portion of the bearing housing bracket 60. A plurality of fixing holes 65 are formed through a connection portion 63 formed around the opening 61 so that the connection portion 63 is fixed to the fringe portion 52 through the fixing holes 65, and a plurality of fixing holes 66 are formed through an edge portion 62 of the bearing housing bracket 60 so that the edge portion 62 is fixed to the rear surface 11 a of the tub 11 through the fixing holes 66.

In order to fix the bearing housing bracket 60 to the rear surface 11 a of the tub 11, the body portion 51 of the housing 50 passes through the opening 61 of the bearing housing bracket 60, and the fixing holes 65 formed through the connection portion 63 of the bearing housing bracket 60 and fixing holes 55 formed through the fringe portion 52 of the bearing housing 50 are connected by fasteners such as bolts 64, thereby connecting the bearing housing 50 and the bearing housing bracket 60.

When the bearing housing 50 and the bearing housing bracket 60 are fixed to each other as described above, a plurality of the fixing holes 66 formed through the edge portion 62 of the bearing housing bracket 60 coincide with a plurality of fixing holes 18 formed through the rear surface 11 a of the tub 11, thereby being easily connected to the fixing holes 18 by fasteners such as bolts 68.

By fixing the bearing housing 50 and the bearing housing bracket 60 to each other and fixing the bearing housing bracket 60 and the rear surface 11 a of the tub 11 to each other as described above, the bearing housing 50 can be firmly fixed to the tub 11.

Under the condition that the bearing housing bracket 60 is fixed to the tub 11, the rotary shaft 30 is inserted into the pulley 31, and a bolt 73 is inserted into the rotary shaft 30. Thereby, the rotary shaft 30 and the pulley 31 are fixed to each other so that the pulley 31 is not separated from the rotary shaft 30.

The bearing housing bracket 60 of the drum washing machine of the present invention serves to connect the bearing housing 50 to the tub 11. When the rotary drum 12 is rotated at a high speed in a dehydration operation, laundry leans to one side and the rotary drum 12 is eccentrically rotated due to the lean of the laundry, thereby generating severe vibration and noise. Here, the bearing housing bracket 60 further serves as a balance weight for applying weight to the tub 11 so as to prevent the generation of vibration. In order to serve as the balance weight, the bearing housing bracket 60 must have at least a designated weight. In this embodiment of the present invention, the weight of the housing bracket 60 is set to 6 kg±200 g. In order to have a weight of approximately 6 kg, the bearing housing bracket 60 must have a considerable thickness. In order to have such a thickness, preferably, but not necessarily, the bearing housing bracket 60 is manufactured by casting. Further, since the bearing housing bracket 60 requires a low volume and a high weight, the bearing housing bracket 60 is made of a material having high specific gravity. Preferably, but not necessarily, the bearing housing bracket 60 is made of cast iron having excellent castability and a specific gravity of approximately 7.5.

A balance weight 70 prepared separately from the bearing housing bracket 60 is detachably attached to the rear surface 11 a of the tub 11 by bolts 71.

Both the bearing housing bracket 60 serving as a balance weight and the balance weight 70 are attached to the rear surface 11 a of the tub 11. The tub 11 is stabilized by concentrating the heavy members 60 and 70, serving as balance weights, on the rear surface 11 a of the tub 11. The above structure causes the tub 11 to be fixed to the housing 10 under the condition that the tub 11 is downwardly inclined such that the rear surface 11 a of the tub 11 is lower than the front surface 11 b of the tub 11.

Further, the degree of eccentric rotation of the rotary drum 12, which is generated when the rotary drum 12 is rotated, is decreased by locating the gravity center of the tub 11 close to the rotary shaft 30 rotating and supporting the rotary drum 12.

When the rotary drum 12 is rotated at a high speed, the rotary drum 12 is eccentrically rotated by the partial disposition of laundry therein, thereby causing distortion of the bearing housing 50 supporting the rotary shaft 30. Conventionally, when the distortion is transmitted to the tub 11, the rear surface 11 a of the tub 11 is cracked. However, in the exemplary embodiment of the present invention, the heavy bearing housing bracket 60 and balance weight 70 are installed on the central portion of the rear surface 11 a of the tub 11 at the center of the rotary shaft 30, thereby reducing the degree of eccentric rotation of the rotary drum 12 and preventing any cracking of the rear surface 11 a of the tub 11.

FIG. 3 is a perspective view of the bearing housing and the bearing housing bracket of the drum washing machine of the present invention in a state in which the bearing housing and the bearing housing bracket are connected.

As shown in FIG. 3, the bearing housing 50 is simply fixed to the rear surface 11 a of the tub 11 under the condition that the bearing housing 50 is surrounded with the bearing housing bracket 60. The bearing housing bracket 60 is connected integrally to the rear surface 11 a of the tub 11 by a plurality of the bolts 68, thereby preventing cracks generated on the rear surface 11 a of the tub 11 by the distortion of the rotary shaft 30 due to the eccentric rotation of the rotary drum 12.

The balance weight 70 is installed at the upper part of the left side of the rear surface 11 a of the tub 11. Since a heavy device, such as a heater (not shown), is installed on the right side of the tub 11, the balance weight 70 serves to maintain the balance of weights between the left and right sides of the tub 11. That is, the balance weight 70 serves to apply weight to the tub 11 for reducing the vibration of the tub 11 and to maintain the balance of weights between the left and right sides of the tub 11.

A plurality of fixing holes 53, which are separated from each other by a designated interval, are formed through the rear surface 11 a of the tub 11 so as to change the installation position of the balance weight 70.

In contrast to the above embodiment, if a heavy device is installed on the other side of the tub 11, the balance weight 70 is installed on the opposite side of the tub 11 from the heavy device for maintaining the balance of weights between both sides of the tub 11.

In the present invention, the bearing housing bracket 60 serves as a main balance weight, and the balance weight 70 provided separately from the bearing housing bracket 60 serves to assist the function of the bearing housing bracket 60 and to maintain the balance of weights between the left and right sides of the tub 11. For this reason, preferably, but not necessarily, the weight of the bearing housing bracket 60 is at least three times the weight of the balance weight 70.

FIG. 4 is a sectional view illustrating the connection structure between the bearing housing and the bearing housing bracket in accordance with a first embodiment of the present invention.

As shown in FIG. 4, in order to integrally fix the bearing housing 50, the bearing housing bracket 60, and the rear surface 11 a of the tub 11, the bearing housing 50 is inserted into the rear surface 11 a of the tub 11. Thereafter, the bearing housing bracket 60 is fixed to the bearing housing 50 using the bolts 64. Finally, the bearing housing bracket 60 is connected to the rear surface 11 a of the tub 11 using the bolts 68. Thereby, the fixation of the above three members is completed.

As shown in FIG. 4, the thickness of the bearing housing bracket 60 is gradually reduced from the opening 61 to the edge portion 62. This reduced thickness of the bearing housing bracket 60 concentrates the weight thereof at a portion close to rotary shaft 30, thereby reducing the degree of eccentric rotation of the rotary drum 12.

FIG. 5 is a sectional view illustrating the connection structure between the bearing housing and the bearing housing bracket in accordance with a second embodiment of the present invention.

As shown in FIG. 5, the bearing housing 50 and the bearing housing bracket 60 serving as a balance weight are unitarily formed as one piece. By forming an assembly 70 obtained by unitarily assembling the bearing housing 50 and the bearing housing bracket 60, it is possible to omit components, such as bolts for connecting the two members 50 and 60, thereby reducing the number of steps of an assembly process of the washing machine, thus improving productivity.

As apparent from the above description, the present invention provides a drum washing machine, in which a bearing housing bracket serves as a balance weight, thereby reducing the number of balance weights attached to a tub, thus reducing the number of steps of an assembly process and improving efficiency in assembling the drum washing machine, compared to a conventional drum washing machine.

Further, the drum washing machine of the present invention causes the gravity center of the tub to be close to a rotary shaft, thereby decreasing the degree of eccentric rotation of a rotary drum.

Moreover, the drum washing machine of the present invention uses a balance weight detachably attached to the rear surface of the tub, thereby easily maintaining the balance of weights between the left and right sides of the tub.

Although exemplary embodiments of the invention have been shown and described, it will be appreciated by those skilled in the art that changes may be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the claims and their equivalents. 

1. A drum washing machine comprising: a tub; a rotary drum installed in the tub; a rotary shaft extended from the rotary drum to the outside of the tub by passing through the tub; a bearing housing installed on the tub for supporting the rotary shaft; and a bearing housing bracket fixing the bearing housing to the tub, and serving as a balance weight for reducing vibration generated due to the eccentric rotation of the rotary drum.
 2. The drum washing machine as set forth in claim 1, further comprising a separate balance weight detachably attached to the tub separately from the bearing housing bracket.
 3. The drum washing machine as set forth in claim 2, wherein the bearing housing bracket and the separate balance weight are installed on the rear surface of the tub.
 4. The drum washing machine as set forth in claim 3, wherein the weight of the bearing housing bracket is at least three times the weight of the separate balance weight.
 5. The drum washing machine as set forth in claim 1, wherein the bearing housing bracket is made of cast iron.
 6. The drum washing machine as set forth in claim 5, wherein the bearing housing bracket includes: an opening formed through the central portion thereof for passing the bearing housing; and an edge portion, through which a plurality of fixing holes are formed so that the bearing housing bracket is fixed to a rear surface of the tub by fasteners passing through the fixing holes.
 7. The drum washing machine as set forth in claim 6, wherein a thickness of the bearing housing bracket is gradually reduced from the opening to the edge portion.
 8. The drum washing machine as set forth in claim 1, wherein the tub is fixed to a housing so that the tub is downwardly inclined from a front surface of the tub to a rear surface of the tub.
 9. The drum washing machine as set forth in claim 1, wherein the bearing housing and the bearing housing bracket are unitarily formed. 